The origin and expansion of the Tupi linguistic family are controversial but there is consensus on two areas: a common Amazonian centre of origin and Tupi differentiation through distinct cultural and historic processes. Their expansion is considered as the largest migration on a continental level. The current investigation was done to test if the expansion model proposed by linguists, archaeologists and morphologists agrees with the variation found in DNA found in Tupi and Je speakers in nine populations located in their route of dispersion. The results indicate that the Tupi and Je speakers underwent radically different patterns of dispersal and unraveled a complex history of the South American prehistoric colonization.
Homo sapiens have experienced an extraordinary migration, inhabiting all continents except Antarctica. Arrival in the Americas happened more recently through one or more streams coming from Asia. This migration brought a high level of cultural and genetic differentiation among groups. In this study, it was found that there were remarkable differences between the Tupi and Je expansions. Tupi speakers radically expanded into new territories having great diversity since they moved farther away from their origin and gained isolation.
The Tupi villages that dispersed long ago may have higher genetic similarity than other groups that separated recently. Fissions occur along kinship lines and they are associated with social tensions like warfare, sorcery, revenge, disease, etc. The absence of significant correlation between genetic distances may be due to related females whose DNA will be present in new village but not in the original one; gene flow when villages may have fused again after forgetting the reasons for fission; Post Columbian women movements which are more recent, and any inaccuracies which may exist in the historical dates of split. It is also possible that the Tupi expansion was characterized by some level of absorption of the Tupi women, and this includes Je speaking women who arrived in South 1000 years prior to the Tupis.
The Je speakers followed an intricate and non-linear mode of dispersion. Both groups portrayed traces of ancient fission-fusion processes moderated by women. The Je did not produce congruent genetic, geographic or historical scenarios and this can be ascribed to socio-cultural factors. An example is that the fusion may be prevented by the presence of fissions that occurred a few generations ago and remained in the collective memory of these groups.